青藏高原特有属——固沙草属表型变异及其对环境因子的响应

该研究通过测量固沙草属(Orinus)3个物种(青海固沙草、固沙草和居间固沙草)的40个天然居群145个个体的22个表型性状,依据VIF膨胀系数筛选得到年平均降雨(MAP)等9个气候因子和海拔等因子,并采用冗余分析(db-RDA)考察不同物种、不同居群植物表型多样性与多元地理气候环境的关系,探讨该属植物表型多样性驱动机理。结果显示:(1)基于22个植物表型性状,固沙草属天然居群在组内最小方差(Ward)55时可归为2类,居群间表型性状不存在显著的空间自相关性(P 0.05),植物表型多样性高(Shannon-Wiener index,H:1.045～2.734),17个定量的表型性状变异系数(CV)平均值47.84%,而居群间小穗颜色多样性最低(H:0.170),证明固沙草属植物表型性状具有独特的环境响应模式。(2)巢式方差分析显示,固沙草属植物表型在居群间和居群内均存在丰富的变异(F 10,P0.01),旗叶、颖片和外稃分别是主成分分析中表型总变异的重要组成部分,表型分化系数居群间变异(71.10%)大于居群内(28.90%),固沙草属植物表型变异来源于居群间。(3)冗余分析结果表明,海拔(ALT)和年平均风速(Wind)是决定青海固沙草(O.kokonoricus)和固沙草(O.thoroldii)居群间表型差异性的主要影响因子;极端气候条件[最冷季平均温度(Bio9)和最干季降雨量(Bio14)]对固沙草居群间表型相似性起促进作用,相反干燥度指数(AI)与水气压(Vapr)对其差异性起促进作用;居间固沙草(O.intermedius)居群间表型差异受年均降雨(MAP)、潜在蒸散(PET)和水气压(Vapr)影响。研究认为,固沙草属植物天然居群之间表型变异反映出明显的地理气候变化趋势,这些表型变异是高山植物环境适应性的重要标志。     

基于形态和叶表皮微形态特征试论西藏固沙草的归并

通过形态学性状的观测、统计和叶表皮微形态特征的分析,比较了西藏固沙草、固沙草和鸡爪草3个近缘物种的主要性状差异,以探讨西藏固沙草的系统分类归属。结果显示,在外部形态上西藏固沙草与固沙草差异甚小,难以进行区分,但与鸡爪草差异明显,是典型的种间关系;在叶表皮微形态解剖上,西藏固沙草的绝大多数特征与固沙草的一致或类同,可与鸡爪草却存在明显间断。故研究认为,西藏固沙草与固沙草是同一个种,西藏固沙草应作为固沙草的异名。     

青藏高原固沙草属种质资源收集和保存

固沙草属(Orinus)是禾本科具有重要经济价值的高山特有属,具有较强的抗逆特性,是农业良种繁育、畜牧业牧草改良利用的重要资源.该属记载6个物种,均分布在青藏高原.在过去5年内,我们调查了该属所有物种在青藏高原的分布,并收集了种子、DNA材料和标本;采用ITS序列对物种界限进行了探讨,发现6个物种中只出现两个比较明显的遗传分支,表明原有的一些物种在分类上应予以合并.我们进一步讨论了这些丰富的种质资源对将来研究和利用固沙草属的重要性和相关途径.     

根据广义形态性状和nrDNA ITS序列试论长颖固沙草的归并

固沙草属是禾本科中一个具有重要经济价值的高山特有属,共记载6个物种,它们均具有较强的抗逆特性,是农业良种繁育、畜牧业牧草改良利用的重要资源;并且,固沙草属物种形态差异不显著,种间界限较模糊。本研究通过广义形态性状的观测、统计和分析,同时结合核基因组ITS片段的研究,系统探讨了长颖固沙草、固沙草和鸡爪草3个近缘物种的主要形态性状和分子序列的差异,旨在评判长颖固沙草的系统分类归属。研究表明,在广义形态性状上长颖固沙草与固沙草差异甚小,难以进行区分,但与鸡爪草差异明显,是典型的种间关系;从基于ITS序列构建的系统发育树看,3个物种中只形成两个比较明显的遗传分支,一个分支是由长颖固沙草和与固沙草所测个体构成,另一分支仅由鸡爪草所测个体组成,并且分支的靴带支持率高达100%。故本研究认为,长颖固沙草与固沙草应是同一个物种,长颖固沙草应作为固沙草的异名处理。     

青海固沙草属的两个新纪录种

首次报道了青海固沙草属2 新记录种--固沙草和鸡爪草, 并对两种植物地理分布上过去的不完善认识进行了分析, 编制了区分该属4 种植物的分类检索表, 同时引证了存于中国科学院西北高原生物研究所两记录种的全部考证标本。     

西藏东南部柏木属群落类型及物种多样性

西藏东南部柏木属植物群落是青藏高原天然林资源的重要组分,在维持高原生物多样性与生态安全方面作用显著.为明确其群落类型及物种多样性,本研究通过在米林县、朗县和波密县设置典型样地和划分群落类型,分析了不同群落物种组成、物种多样性指数及建群种径级结构.结果表明: 柏木属植物群落可划分为4个群落类型:西藏柏木-柳叶忍冬+绒毛山梅花-凤尾蕨+紫马唐群落(群落Ⅰ)、巨柏-圆锥山蚂蝗+砂生槐-线形草沙蚕+芸香草+固沙草群落(群落Ⅱ)、巨柏-甘肃野丁香-杂配藜+固沙草群落(群落Ⅲ)、巨柏-小蓝雪花-藏沙蒿+固沙草+蒺藜群落(群落Ⅳ).各群落Margalef丰富度指数、Shannon多样性指数、Pielou均匀度指数及种间相遇机率指数均表现为:群落Ⅰ＞群落Ⅱ＞群落Ⅲ＞群落Ⅳ.4个群落的建群种幼龄级个体多而中老龄级少,植株由幼龄级向中龄级过渡阶段死亡率较高,柏木属植物种群呈衰退趋势.     

披碱草属及其近源属植物种子胚乳细胞多样性研究

披碱草属不仅是小麦、大麦等作物的重要基因库,也是优良牧草的重要组成部分。胚乳是麦类作物种子的重要组成部分,其重量占籽粒重量在90%以上。胚乳特性是一个相对稳定的遗传性状,可以将胚乳特性作为植物分类和系统关系的一个指标。胚乳细胞特征作为植物的一类微形态特征,在麦类植物系统分类与进化研究中具有一定的价值。该研究对小麦族的6个披碱草属(Elymus)物种、2个拟鹅观草属(Pseudoroegneria)物种、1个大麦属(Hordeum)物种和2个冰草属(Agropyron)物种,共4属11份材料的胚乳细胞特征进行解剖观察并测量相关指标。结果表明:(1)不同属、种的植物种子胚乳细胞之间存在丰富的多样性,属间差异大于属内种间差异;(2)同样具有P染色体组的Agropyron cristatum和A.mongolicum与同样具有St染色体组的Pseudoroegneria libanotica和P.spicata各自在细胞形状和大小上的差异很小;(3)不同物种的胚乳细胞在大小、形状和数量上均表现出差异,但不能很好地反映属以及基因组间的差异,研究结果为揭示披碱草属植物的系统关系提供了胚乳细胞方面的证据,同时也为利用该属植物改良麦类作物品质积累资料。     

鹅观草属、披碱草属、猬草属和仲彬草属物种的RAMP分析及系统学意义

对鹅观草属、披碱草属、猬草属和仲彬草属4属23个物种进行了RAMP分析。结果表明属间变异极大,多态性极高。31个引物组合产生的286条DNA扩增片段均具有多态性。聚类分析显示鹅观草属、披碱草属、猬草属和仲彬草属物种各自聚为一类;Roegneria alashanica、R．elytrigioides和R．magnticaespes聚类在一起;猬草属的模式种Hystrix patula与披碱草属物种聚类在一起,而Hystrix duthiei和H．longearistata单独聚为一类;形态相似、染色体组相同、地理分布一致的物种聚类在一起。本研究结果基本上同形态学和细胞学研究结果相吻合,将鹅观草属、披碱草属和仲彬草属作为属分类等级处理比较恰当,而猬草属的系统地位有待进一步确认。RAMP标记可作为评价多年生小麦族物种遗传多样性和亲缘关系的一种分子标记技术。     

小麦族鹅观草属、披碱草属、猬草属和仲彬草属细胞质基因组PCR-RFLP分析

对鹅观草属、披碱草属、猬草属和仲彬草属23个物种和1份外类群共24份材料进行了细胞质基因组PCR-RFLP分析。3个叶绿体和3个线粒体通用引物扩增出的片段,用15种限制性内切酶对其进行酶切。在47种引物/酶组合中,获得329条DNA片段,其中304条具有多态性,占92.4%。结果表明鹅观草属、披碱草属、猬草属和仲彬草属材料存在属间和种间多态性,遗传相似系数较高。聚类分析显示仲彬草属单独聚为一类,鹅观草属R. grandis、R. aristiglumis、R. elytrigioides、R. alashanica、R. magnicaespes聚为一类,R. caucasica、R. ciliaris、R. amurensis、R. japonensis聚在一起,5个披碱草属材料、3个猬草属材料和1个鹅观草属物种R. kamoji聚为一类。这些结果与前人对其进行的RAPD和RAMP分析的结果基本一致。仲彬草属作为属分类等级处理是恰当的,对于鹅观草属、披碱草属和猬草属的系统地位和一些物种的分类处理,有待进一步研究。     

根据叶表皮特征试论国产三齿稃亚族的属间关系

根据植物叶片表皮结构,尤其下表皮特征,对国产三齿稃亚族6个属(包括1个引进属)进行了属间关系的分析。结果表明：国产三齿稃亚族中固沙草属最原始,草沙蚕属最高级,双稃草属、千金子属、三齿稃属和隐子草属演化居于其间;隐子草属可能直接起源于固沙草属,并在自身基础上派生了较为高级的三齿稃属;双稃草属与千金子属渊源关系直接,前者可能通过后者问接起生于固沙草属;草沙蚕属具有别于它属的性状级次,可能是起源于固沙草属、独树1支的顶级类群。这一结果不仅修正了前人演化理论的差误,而且为今后探讨该亚族的地理起源、散布路线提供了资料。     

A population genetics perspective on the evolutionary histories of three clonal,endemic, and dominant grass species of the Qinghai–Tibet Plateau: Orinus (Poaceae)

We performed analyses of amplified fragment length polymorphism (AFLP) in order to characterize the evolutionary history of Orinus according to its population genetic structure, as well as to investigate putative hybrid origins of O. intermedius and to provide additional insights into relationships among species. The genus Orinus comprises three clonal grasses that are dominant species within xeric alpine grasslands of the Qinghai–Tibet Plateau (QTP). Here, we used eight selectively obtained primer pairs of EcoRI/MseI to perform amplifications in 231 individuals of Orinus representing 48 populations and all three species. We compared our resulting data to genetic models of hybridization using a Bayesian algorithm within NewHybrids software. We determined that genetic variation in Orinus was 56.65% within populations while the among‐species component was 30.04% using standard population genetics statistics. Nevertheless, we detected that species of Orinus were clustered into three highly distinct genetic groups corresponding to classic species identities. Our results suggest that there is some introgression among species. Thus, we tested explicit models of hybridization using a Bayesian approach within NewHybrids software. However, O. intermedius likely derives from a common ancestor with O. kokonoricus and is probably not the result of hybrid speciation between O. kokonoricus and O. thoroldii. We suspect that recent isolation of species of Orinus in allopatry via vicariance may explain the patterns in diversity that we observed, and this is corroborated by a Mantel test that showed significant positive correlation between geographic and genetic distance (r = 0.05, p < 0.05). Recent isolation may explain why Orinus differs from many other clonal species by exhibiting the highest diversity within populations rather than among them.     

Is Oryza malampuzhaensis Krish. et Chand. (Poaceae) a valid species? Evidence from morphological and molecular analyses

Phylogenetic relationship between O. malampuzhaensis Krish. et Chand. (2n = 4x = 48; Poaceae, Oryzeae), a South Indian endemic wild rice with a disputed taxonomic identity, and eight other species belonging to the O. officinalis complex of the genus Oryza was examined using 62 morphological characters and 445 random amplified polymorphic DNA (RAPD) markers. Multivariate and cluster analyses using both the data sets clearly separated all accessions of O. malampuzhaensis into a distinct group. Genetic distances between O. malampuzhaensis and other species in O. officinalis complex were comparable with the distance between any other two taxa with species rank in this complex. Case-by-case taxonomic treatment of O. malampuzhaensis in relation to other species examined is presented. A taxonomic key for the discrimination of O. malampuzhaensis from other species in the O. officinalis complex has been constructed. Based on the present results, we strongly argue to restore the species rank to O. malampuzhaensis, as originally proposed by Krishnaswamy and Chandrasekharan (1958).     

Phylogenetic Analysis of AA-genome Oryza Species (Poaceae) Based on Chloroplast, Mitochondrial, and Nuclear DNA Sequences

Species in the genus Oryza (Poaceae) contain 10 genomic types and are distributed in pan-tropics of the world. To explore phylogenetic relationships of Oryza species having the AA-genome, DNA sequences of the chloroplast trnL intron and trnL-trnF spacer, mitochondrial nad1 intron 2, and nuclear internal transcribed spacer were analyzed, based on materials from 6 cultivated (O. sativa and O. glaberrima) and 13 wild accessions, in addition to a CC-genome species (O. officinalis) that was used as an outgroup. Analyses of the combined sequence data set from different sources provide a much better resolution of the AA-genome species than the individual data set, indicating the limitation of a single gene in phylogenetic reconstruction. The phylogeny based on the combined data set demonstrated an apparent grouping of the AA-genome Oryza species that was well associated with their geographic origin, although the Australian O. meridionalis showed its affinity with the African species. The geographic pattern of the phylogenetic relationship was probably attributed to the frequent genetic exchange and introgression among the AA-genome species from the same continents. In addition, Asian cultivated rice O. sativa showed its close relation to O. rufipogon and O. nivara, whereas African cultivated rice O. glaberrima was closely linked to O. barthii and O. longistaminata, indicating the independent domestication of the two cultivated species in different geographic locations.     

赖草属植物的分类现状及主要存在的问题

赖草属(Leymus Hochst.)为禾本科(Poaceae)小麦族(Triticeae)中的一个有重要经济价值的属,属内多数种类是优良牧草,有些种类具有耐寒、耐旱、耐碱等特性,是农业良种繁育、畜牧业牧草改良利用的重要基因资源。该属在分类学上是一个疑难属,在属的界限、属下组系的划分,以及类群间演化关系上问题较多。对赖草属分类学问题进行了综述,为赖草属植物资源的开发利用和保护提供资料。     

<Emphasis Type="Italic">Phuphanochloa,</Emphasis> a new bamboo genus (<Emphasis Type="Italic">Poaceae</Emphasis>: <Emphasis Type="Italic">Bambusoideae</Emphasis>) from Thailand

Summary  A new monotypic bamboo genus Phuphanochloa (Poaceae: Bambusoideae) from north-eastern Thailand is described, together with a new species, P. speciosa.     

广西禾本科植物二新记录属

该文报道了广西禾本科(Poaceae)植物二新记录属,即菵草属( Beckmannia Host)和草沙蚕属( Tripogon Roem. et Schult.)。菵草属有2种及1变种,分布较广,我国有1种1变种,广西首次记录到该属的菵草[ Beckmannia syzigachne (Steud.) Fern.]。草沙蚕属约有30种,多分布于亚洲和非洲,我国有11种,广西首次记录到该属的线形草沙蚕( Tripogon filiformis Nees ex Steud.)。同时,还提供了2个新记录属、种的形态描述与照片。     

A biosystematic study of theOryza meyeriana complex (Poaceae)

To determine the taxonomic status and to clarify the biosystematic relationships of wild rice species, i.e.,Oryza granulata andO. meyeriana in theO. meyeriana complex (Poaceae), a series of intraspecific and interspecific hybridization experiments, genomic analyses through meiotic pairing, and morphological studies were conducted. Hybridization results demonstrate comparatively high crossability with about 34–39% of seed set, and very limited reproductive isolation betweenO. granulata andO. meyeriana. Chromosome pairing in the parental species and their F₁ hybrids indicate very high genomic affinity between the two taxa. Morphological analyses of the parental accessions and their intra- and interspecific hybrids show a large variation among the samples included, but no appreciable grouping was observed. The traditionally used character, i.e., spikelet length, does not contribute significantly to the grouping of the samples included. Based on the facts that the two taxa have negligible reproductive barriers and share almost identical genomes, the authors believe thatO. granulata andO. meyeriana do not warrant separate taxonomic status, and recommend that they be combined asOryza granulata.     

新疆列当的种类、分布及其防治技术研究进展

列当是一种根寄生种子植物,是我国进境植物检疫对象,同时也是我国的内检对象。新疆是我国列当发生面积最大、危害最重和种类最多的地区,对新疆的主要经济作物,如加工番茄、向日葵、甜瓜等已造成严重危害。在新疆文献记载的列当种类有18种,常见的有埃及列当、大麻列当、向日葵列当和弯管列当,并已广泛分布于新疆各县、市、团场。列当的防治技术主要包括检疫、田间管理、轮作等,但目前的防治效果均不理想。本文通过对新疆列当的相关文献搜集、整理分析,总结了目前新疆列当的种类、分布情况,以及综合防治技术,为今后列当的研究和防治提供参考。     

Evolutionary modes of emergence of short interspersed nuclear element (SINE) families in grasses

Short interspersed nuclear elements (SINEs) are non‐autonomous transposable elements which are propagated by retrotransposition and constitute an inherent part of the genome of most eukaryotic species. Knowledge of heterogeneous and highly abundant SINEs is crucial for de novo (or improvement of) annotation of whole genome sequences. We scanned Poaceae genome sequences of six important cereals (Oryza sativa, Triticum aestivum, Hordeum vulgare, Panicum virgatum, Sorghum bicolor, Zea mays) and Brachypodium distachyon to examine the diversity and evolution of SINE populations. We comparatively analyzed the structural features, distribution, evolutionary relation and abundance of 32 SINE families and subfamilies within grasses, comprising 11 052 individual copies. The investigation of activity profiles within the Poaceae provides insights into their species‐specific diversification and amplification. We found that Poaceae SINEs (PoaS) fall into two length categories: simple SINEs of up to 180 bp and dimeric SINEs larger than 240 bp. Detailed analysis at the nucleotide level revealed that multimerization of related and unrelated SINE copies is an important evolutionary mechanism of SINE formation. We conclude that PoaS families diversify by massive reshuffling between SINE families, likely caused by insertion of truncated copies, and provide a model for this evolutionary scenario. Twenty‐eight of 32 PoaS families and subfamilies show significant conservation, in particular either in the 5′ or 3′ regions, across Poaceae species and share large sequence stretches with one or more other PoaS families.